1. Field of the Invention
The present invention relates to a plug for use in a beverage container such as a thermos bottle. Particularly, the present invention relates to a plug having a valve structure, and allowing a content fluid to be poured out when attached to a beverage container.
2. Description of Related Art
Conventionally, a plug for use in a beverage container comprises a plug main body having a fluid passage allowing a content fluid to be poured therethrough when tilting the beverage container and a valve structure capable of opening and sealing the fluid passage. The valve structure includes: a valve shall provided in the plug main body and capable of moving up and down; a valve body supported in a lower end of the valve shaft and capable of opening and sealing the fluid passage; a biasing means biasing the valve body in a sealing direction; and a control lever allowing the valve body to be opened when pushed down against a biasing force generated by the biasing means. The plug main body includes an opening formed in as top panel and allowing a pushing portion of the control lever to be protruded outward.
Such plug easily becomes dirty with boiler scale or the like because the content fluid contacts the valve body and/or the valve shaft when poured. In order to wash the valve body, the valve shaft and the fluid passage, the plug is disassembled and then washed. For example, a plug for use in a beverage container disclosed in Japanese Unexamined Patent Application Publication No. 2002-65709 includes: a pair of engagement arms provided on a base end of a control lever abutted onto as distal end of a valve shaft; an insert hole formed on each engagement arm; a shaft pivotably supporting the control lever relative to a plug main body and inserted into the insert hole; a guide groove formed at a lower portion of the insert hole and guiding the shaft to the insert hole; and a boss formed in a hemisphere shape and protruded adjacent to the insert hole. When washing this plug, 1) rotating the control lever in an anti-operational direction, 2) taking out the shaft from the insert hole and then removing the control lever by widening a distance between engagement arms using the boss, 3) taking out the valve shaft, the valve body and the biasing means from the plug main body, and then allowing the valve structure to be washed.
Further, as a plug of such kind, there has been disclosed an inner plug structure (e.g., Japanese Patent No. 4514692) for use in a fluid container. This inner plug structure includes: an inner plug main body detachably attached to an opening section of a container main body; a fluid passage that is thrilled inside the inner plug main body, and connects an inlet and an outlet that are respectively opened toward an inner side and an outer side of the container main body; a valve body biased in a direction allowing the inlet of the fluid passage to be closed; a cover that is disposed on an upper end of the inner plug main body and serves to close an upper opening section thereof; and a control switch that is provided on the cover and is capable of being slid back and forth such that the valve body can be opened and closed. Further, while a first engagement portion is provided on either one of the inner plug main body and the cover, a first engageable portion engageable with the first engagement portion is provided on the other. Here, an elastic section is provided on the upper end of the inner plug main body. Particularly, while a second engagement portion is provided on either one of the elastic section of the inner plug main body and the cover, a second engageable portion engageable with the second engagement portion is provided on the other. This inner plug structure is simpler than a conventional structure where coupling portions are provided on whole circumferences of the inner plug main body and the cover. Moreover, since a force used to slide the control switch is applied in a horizontal direction, i.e., a direction other than a disengagement direction, the inner plug structure shall not be disassembled involuntarily.